Cancer illnesses, i.e. malignant tumor formations, are often accompanied by numerous changes in the external appearance of a patient. In the past, these changes have been detected only qualitatively by a medical practitioner in the context of a diagnosis, and therefore essentially reflect a sense of the physician for the state of health of the patient. The assessment of the external appearance in this case requires considerable medical experience, which can generally only be gained through many years of professional practice. In the case of practitioners with limited or no experience in particular, the risk of an incorrect assessment is therefore correspondingly high. Moreover, the purely qualitative assessment of the external appearance is only a poor and relatively inconclusive indicator of the actual state of health of the patient, and always reflects a personal and subjective impression of the examiner.